When a reporter asked if Bunning's decision to keep the poll numbers private infers that he isn't happy with the results, he responded: "You are going to infer any damn thing you choose, so why should I try to influence it."

For the past few months, Bunning has sparred with members of GOP leadership and the media as both questioned whether the senator can mount a strong bid for a third term. For weeks, reporters pressed and Bunning promised to share the results of a campaign poll conducted in late February. The results are seen as a critical test of Bunning's viability to potential campaign donors and voters.

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Traditionally, incumbents look for two basic things in internal polls to assess their political health: ballot support above or close to 50 percent (with the incumbent getting at least 80 percent support from members of his party and winning handily among independents) and a favorable image, said Neil Newhouse, a partner and GOP pollster at Public Opinion Strategies.

It is unclear whether Bunning has met that threshold.

"If the news had been good they would have released it to quiet the critics and help with fund-raising," said Jennifer Duffy, a senior analyst with the Cook Political Report.

Bunning will also need to ramp up efforts to get key campaign staffers in place to adequately handle this phase of what will likely prove a high profile campaign.

"He should have a full time fund-raiser. They don't need a media consultant right now, but at this point he should at least know who the manager is going to be," Duffy said.

Bunning is still searching for a campaign manager. Though he has a fund-raising staffer in Kentucky and another fund-raiser in Washington D.C, he has also struggled to raise money.

Bunning's campaign reported having about $150,000 on hand as of the most recent Federal Election Commission filing — far less than the $1 million to $2 million that political experts suggest Bunning would need by the end of the first quarter to mount a successful run.

"If Senator Bunning's goal has been to raise money, it sure looks like he's kept that a closely guarded secret, and he's only got himself to blame for it," Newhouse said. "After all, at its base, fund-raising success is usually a function of popularity."

Bunning is quite unpopular among some segments of the Republican Party these days.

Bunning, a Hall of Fame pitcher, has railed against fellow Kentuckian, Senate Minority Leader Mitch McConnell, and the National Republican Senatorial Committee’s chairman, Sen. John Cornyn of Texas, over support for his re-election efforts.

In January, McConnell told reporters at the National Press Club in Washington that he didn't know if Bunning planned to seek re-election. Bunning said the senior senator must have suffered a memory lapse because Bunning told McConnell of his re-election intentions in early December.

Cornyn made similar comments but has since said the NRSC fully supports Bunning’s campaign efforts.

According to reports in several publications, Bunning told lobbyists at a National Mining Association fund-raiser last month in Washington that he would resign if he is unable to raise money and garner broader support in his campaign for a third term. Bunning denied the reports.

Both McConnell and the NRSC declined to comment on the reports of Bunning's threat to resign.

Bunning's public slips of the tongue make some GOP insiders cringe, further undermining his support.

Last month, Bunning said U.S. Supreme Court Justice Ruth Bader Ginsburg, who's being treated for pancreatic cancer, would be dead by year’s end. Bunning apologized for the statement.

But beyond the bluster over insults and in fighting, numbers remain Bunning's biggest challenge.

Senate candidates that would otherwise be considered "safe" tend to have large war chests and savvy staffs at the ready, Duffy said. Sen. Richard Shelby, R-Ala., has millions stashed for his re-election bid and Sen. Susan Collins, R-Maine, a favorite target of Democrats, is often financially prepared to rebuff challengers.

By contrast, former Sen. Elizabeth Dole, R-N.C., had a harder time beating back a challenge from Sen. Kay Hagan, D-N.C during the 2008 elections.

"It was harder for her to play a competitive game because she wasn't ready," Duffy said. "The question is: Does the professional athlete in (Bunning) believe you can come back at the bottom of the ninth?"